Belt tightener



Jan. 10, 1950 s. D. RUSSELL 2,494,360

BELT TIGHTENER Filed Feb. 17, 1945 2 Sheets-Sheet 1 IN V EN TOR.

A TTORNEY Jan. 10, 1950 v s. D. RUSSELL 2,494,360

BELT TIGHTENER Filed F'gb. 17, 1945 I 2 Sheets-Sheet 2 INVENTOR. v v ii W 7 M ATTORNEY Patented Jan. 10, I950 UN I TED STATES T- OFFICE BELT TIGHTENER Stanley D. Russell, 'Racine,*Wis.', assignor to J :1. Case Company, Racine, Wis, .a---.c'or.poration 'of Wisconsin Application February 17, 1915, Serial-No. "578.371

4 Claims. .'(01. v e 242.13)

1 The present invention relates to engine bases or bases for other prime *movers, or mechanism, and particularly to that type-which is movable for adjusting a belt leading from the engine or other mechanism. An object thereof is togenerally improve the construction and operation of devices of this'cl'ass.

A further object is to provide means 'f'or'shifting an engine, or other device having a pulley, s'o-that it can serve the purposes of a clutch and 'a belt tightening idler whereby it is possibleto'd'iis pense with other expedients for these purposes.

A further object is to provide such a structure which will be convenient to install in a variety "of situations because of a certain latitude permissible in the disposition of the parts.

Other objects are to provide 'expedients for the realization of the above objects.

Further objects and advantages Will become apparent from the following specification and the accompanying drawings in which satisfactory embodiments of the invention are shown. new ev-r, it is to be understood that the invention is not limited to the details disclosed but'inclu cles all such variations and modifications as fall within the spirit of the invention as herein ex pressed.

Figure 1 shows a plan view of the engine base applied to a machine such as a baler.

Fig. 2 is a sectional detail of certain mechanism indicated in Fig. 1.

Fig. 3 is a similar view taken on theline 3--3 of'Fig. 1.

Fig. 4 is a. plan view of am'odified installation.

Fig.5 is a side elevation of the same.

Fig. 6 is a sectional view taken substantially on: the line 6--6 of Fig. 8.

Fig. 7 'a sectional view taken on the line 1-1 of Fig. 5.

Fig. 8 is an enlarged detail of certain mechanism indicated in Fig. 4.

the manufacture of farm machinery such for example as balers, loaders, and the like, it is essential that satisfactory mechanism be provided at the very least possible cost. These machines "are commonly driven by internal combustion engines-not adapted to starting readily under load. Furthermore; the simplest convenient drive from such an engine in an inexpensive machine is commonly-a'belt which, with the comparatively short centers; commonly required, ordinarily must have some means for adjusting its tension. This has been accomplished in the past by the use oi some sort of an idler pulley which has been a somewhat troublesome and needless complication.

Also, in order to facilitate starting of theengine, it has "often been provided with a clutch which addsappreciably to the cost and provides one moreplace'which is difiicult to repair in caseo'f failure a'iter long usage.

In the "present instance, the purposes of both of these units are served by a single relatively simple expedient.

' Turning to Figure 1, the device is shown. as. applied to-a baler generally-designated"as B and having a driven wheel or pulley [0 which is connected'to operate the baling and feeding mechanism not shown and forming no part or the present invention. The device comprises a station ary base generally designated as l I and a movable portion or base [2, the movable base being shift able by means of a crank 13 to tighten'and loosen.

a belt Il -disposed about wheel H) and a pulley I5 carried'and operated by engine [6 fastened in any suita'ble manner to movable base 12'.

it is to "be notedthat engine It is ordinarily 'of'substantial weight and causes a considerable friction drag on base II when movable base I! is shifted. Also belt m exerts a reaction against pulley l'5 which is in the same direction as the reaction caused by said friction drag during tightening movement. Crank I3 terminates in a'threaded shaft 1''! which engages base l2, and it 'isto be noted that the-pull of rod I! is exerted on movable base l2 in the opposite direction to the above two forces and between them. Thus, the belt pull andthe friction drag are approximately balanced against each other so that there is no substantial tendency to swing the engine and base awayfrom a position wherein pulley l5 and belt 'I 4 are in proper alignment. Returning to a more complete description of embodiment, base H comprises spaced bars or angle irons l8 and 19 provided with slots 20-40 for guiding movable base l2; Slots 20-21] are traversed by guiding bolts 21-41 as more particularly seen in Fig. 3. Base I 2 comprises bars or angle irons 22 and 23 spaced apart by 'suitab'le braces 24 and '25 and further braced in the presentv instance by the base portion of engine ['6 whereby a rigid rectangular frame is provided which may slide as a unit on base H.

Bars I 8 and [9 are united at one end by a 'cros's'member 26 provided inthe presentinstance an upstanding flange 21. Bolts ll- 21 are preferably threaded into angle irons 2'2 and 2'3 from below, a washer 28 being arranged beneath bar I 9 to provide asatisfa'ctory sliding bearingon the underside of 'the latter. Bolts '21 are ad justeo "toellminate any appreciable "slack or gaging above mentioned flange 21 and preventing endwise movement of shaft 11. Bearing 39 comprises a washer 3| welded or otherwise fixed with shaft 11 and a washer 32 removablymaintained on the shaft in the present instance by a cotter pin or the like 33.

In this class of machinery, tolerances are necessarily quite large and accordingly a very simple type of self-aligning connection, generally designated as 34 is provided between shaft l1 and bar 23 of movable frame 12.

As best seen in Fig. 2, bar 23 has an upstanding flange 35, shaft ll passing freely through an opening 36 therein. A nut 3'! is engaged with shaft l1 and maintained against turning by bolts 38 and 39 having sleeves 40 and 4! for spacing a plate or strap 42 a little beyond nut 31. Shaft I! also passes freely through an opening 43 in strap 42, the latter being maintained against spacers 40 and M by nuts 44 and 45 threaded on bolts 38 and 39 respectively. Thus it will be apparent that nut 31 cannot escape from between flange 35 and strap 42 but that it is free to move slightly in response to any irregularity in the movement of base H or shaft II. A suitable amount of freedom is also provided in thrust bearing 30.

As above stated, shaft I1 is offset and exerts its pull on base [2 at a point between the reaction of belt 14 and the point of application of the friction drag caused by the weight of engine IS. The exact point of application of the force of shaft I! is best determined by experiment but in general it will be so located that the distance transverse to belt [4 from the belt to the shaft will be related to the distance from the shaft to the center of frictional resistanceinversely as the value of the belt pull is related to the value of the frictional resistance. The result isa surprisingly easy shifting of the engine and sensitive and easily controlled tightening of the belt.

-When the belt is to be loosened, the belt of course operates to assist the thrust set up in shaft 1? so that no appreciable excessive resistance is encountered. In fact the action of shaft 1'! is so effective that the engine is readily shifted for starting and stopping the wheel or pulley H] in the manner of a friction clutch thus dispensing with the necessity for this element.

Turning to Figs. 4 and 5, a modification is shown illustrative of the adaptability of the principles involved. In this instance, an engine 46 is installed on a loader generally designated as 41 and which has an upright 48 and a brace 49 which would interfere with the location of a crank 59 in line with a belt 5!, driving parts of the loader not shown.

In this embodiment, a block 52 is fastened on the deck 53 of loader 41 and carries a plate 54 having Slots 55 and 56.

Bolts 5'!-5'l traverse a flange 58, Fig. '7, constituting part of the base of engine 46 and pass through slot 56 to form guides for sliding of the engine on plate 54. A strap 59 is engaged under the heads of bolts 51 and a bearing strip 69 is interposed between flange 58 and plate 54. A spacer 6i surrounds bolt 51 within slot 56 and serves to space a strap 62 a slight distance beneath plate 54. Not 63 clamps the several parts together in rigid relation so that a freely slidable bearing is provided for engine 46 without appreciable up-and-down play.

Bolts 64-64 are provided on the other side of engine 46, the arrangement being substantially identical, although strap 59 may be omitted if desired.

Strap 59, in the present instance, extends to the'left of engine 46, as seen in Fig. 5, and is engaged by a fitting generally designated as 65,

having a threaded bore engaging a threaded shaft 66 connected with crank 50.

Fitting 65 has a neck 61 journaled in a suitable bore in strap 59 and a washer 68 is shouldered 15 3. In a belt tightener and engine base, a

on neck 61 and clamped by a nut 69. Thus fitting 65 may turn freely in strap 59 and sufficient freedom is provided to avoid binding.

Shaft 66, as in case of the Fig. 1 embodiment, engages the unit comprised by engine 46 and straps 59, 69, etc., at a point between the point or center of frictional resistance and the center of pull of the belt. In this manner, there is no objectionable tendency toward swinging of the engine and binding of the bolts 51 and 64 in slots 56 and 55. While the principle of this arrangement is as above described in the previous embodiment, considerable latitude has been found permissible in the location of the parts. In the present instance, because of the encroachment of brace 49, on the space which might be desirable for shaft 69, the latter has been inclined somewhat from a direction parallel to belt 5| and is supported in a bracket 10 fixed on upright 48, a thrust bearing H being provided of a character similar or identical with above mentioned bearing 36. Sufiicient freedom is allowed in bearing H to provide for the slight swinging of shaft 56 due to the movement of engine 46 in a direction which is non-parallel with shaft 65.

By'manipulating crank 59, engine 46 may be readily moved back and forth to tighten or loosen belt 51 about pulley T2.

The above being a complete description of illustrative embodiments of the invention, what is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In a belt tightener, a stationary frame, a movable frame supported on the stationary frame, and means for shifting the movable frame including a threaded shaft engaged between, the stationary frame and the movable frame, said shaft having a thrust bearing on one of said frames, the other frame having an upstanding flange and a nut engaged with the flange and threaded 0n the shaft, spaced studs loosely engaging the nut to prevent turning thereof, and a strap carried by said studs and maintaining said nut floatingly in place against said flange for moving said movable frame in response to turning of said threaded shaft.

2. In a belt tightener and engine base, a pair of spaced slotted longitudinally extending members, a base frame slidable relatively to said longitudinal members, and a plurality of bolts rigidly clamped on said base frame and extending through the slots of said members and freely slidable therein while so clamped in said base frame for relatively free guided movement of said base relatively to said longitudinal members.

slotted support member, a base slidable relatively to said slotted member, and a plurality of bolts rigidly clamped on said base and extending through the slots of said member and freely slidable therein while so clamped in said base 5 for relatively free guided movement of said base relatively to said longitudinal member.

4. In a belt tightener, a prime mover base member, a support member for said base member,

said base member being slidable on said support 10 Nu b member, one of said members being slotted, and a plurality of bolts rigidly clamped on the other member and extending through the slotted portion of the first member and freely slidable therein While so clamped in the other member, 15

for relatively free guided movement of said base member relatively to said support member.

STANLEY D. RUSSELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

